Carbon sources-dependent carotenoid production in metabolically engineered Escherichia coli

The effects of three phosphoenolpyruvate (PEP)-dependent PTS carbon sources (glucose, mannose and maltose) and three non-PTS carbon sources (glycerol, galactose, and lactose) on the formation of four carotenoids with diverse structures and on the cell growth of the recombinant Escherichia coli were investigated. The biosynthetic pathways of four carotenoids, C-30 diapolycopene, C-30 diapotorulene, C-40 lycopene, and C-40 beta-carotene, were engineered in E. coli. The resulting E. coli cells were grown in a mineral medium supplemented with each of the six carbon sources. Among the six carbon sources, non-PTS glycerol showed the highest performance in production of all four carotenoid structures, whereas PTS glucose showed the lowest performance. Based on the conversion yield, carotenoid-producing capability, and the cell density, we found that there was no close correlation between PTS and non-PTS transport mechanism and carotenoid formations in E. coli.